Studies of the distribution of a new human lambda-chain gene will be extended and efforts made to see if it has an unusual association with clases or subclasses of G immunoglobulins. The relation of the new constant region sequences to a hitherto invariant variable region sequence will be investigated to determine whether amino acid residues in the variable region control the type of constant region attached. Sequence studies of the Mcg H-chain will be extended to provide correlating data for the X-Ray structure of the Mcg-IgG. The chemical nature of an L-chain serologic function in the Fc5 microns fragment of an IgM will be explored in terms of there being a third L-chain in IgMs. Studies on the chemical proprties of human superoxide dismutase will be continued and the relationships of its two non-covalently bonded chains explored. Detailed characterization of human alpha-fetoprotein and studies of a possible biologic function for the rat protein will be continued. Definition of the amide losses in human erythrocyte carbonic anhydrase B resulting in in vivo and in vitro formation of the A,D and T forms will be completed. The delineation of the amino acid substitutions responsible for five polymorphic horse low activity erythrocyte carbonic anhydrases and two high activity types will be determined.